The recent image forming apparatus, such as a printer, copier, facsimile, or multifunctional apparatus, may be connected to or disconnected from a finisher that performs post processing such as sorting, binding, or punching onto a recording sheet that is output from the image forming apparatus.
The finisher, which may be optionally provided, may include a controller that controls post processing to be performed by the finisher. The controller may be further provided with a function of suppressing the damage or the inconvenience which may be caused when the finisher does not properly operate. For example, as described in the Japanese Patent Application Publication Nos. 2005-343661, 2005-206264, and 2006-023544, a sheet discharge tray or a paper delivery path may be switched when the failure is detected in the finisher.
However, there may be the case where the sheet discharge tray or the paper delivery path cannot be switched. For example, when the finisher having a sheet discharge tray is installed onto the image forming apparatus of in-body discharge type by mounting the finisher onto a sheet discharge section of the image forming apparatus, the recording sheet can be only output onto the sheet discharge tray of the finisher unless the finisher is removed from the sheet discharge section. In another example, when the finisher shares a paper delivery path with the image forming apparatus, the paper delivery path cannot be switched. In another example, even when the sheet discharge tray or the paper delivery path could be switched to another sheet discharge tray or paper delivery path, the image forming apparatus may not able to determine when to switch the sheet discharge tray or the paper delivery path unless there is an instruction from the finisher as the sheet discharge tray or the paper delivery path that is set by default is controlled by the controller of the finisher.